The diminishing availability of water that is fit for consumption by humans has become a world-wide problem in the last decade. Industrial wastes and household chemicals, as well as leachates from cesspools and septic tanks are finding their way into the aquifers and surface water supplies. People are alarmed by reports of carcinogens and heavy metals, such as lead, cadmium, and the like, in their water.
Many people having lost confidence in the purity of their daily water supply, have chosen alternate supplies of drinking water. These water supplies are obtained by activated carbon filtering, reverse osmosis systems, distillation, and bottled water originating from diverse sources.
Each of these supplies has some disadvantages which are briefly summarized as follows:
Activated carbon filtering removes only organic contaminants and does not remove lead, sodium, nitrates, and the like. Also, the carbon chamber can become a breeding ground for bacteria which find their way into the so-called purified water, and may be harmful. The activated carbon filters must be replaced periodically.
Reverse osmosis systems are expensive to purchase, are energy intensive to operate, and require periodic replacement of expensive components.
Distillation systems are expensive to purchase, expensive to operate, and the heating source must eventually be replaced.
Bottled water is inconvenient and heavy to carry home from the store, and is costly to purchase over a period of time. There is also no guarantee that the quality of the water is that which the user desires and is in fact an improvement over tap water or other readily available water.
Various attempts have been made to purify water by freezing or partial freezing, such as are disclosed U.S. Pat. No. 2,340,721, granted Feb. 1, 1944 to Whitney; U.S. Pat. No. 4,448,032, granted May 15, 1984 to Hibino et al; and U.S. Pat. No. 4,799,945, granted Jan. 24, 1989 to Chang. These systems were complex and costly so as to militate against home use.
It was also known to measure the purity of water by conductivity determinations and other means, such as is disclosed in U.S. Pat. No. 4,762,611, granted Aug. 9, 1988 to Schipper; U.S. Pat. No. 4,496,906, granted Jan. 29, 1985 to Clack; U.S. Pat. No. 3,838,774, granted Oct. 1, 1974 to Dolan etal; and U.S. Pat. No. 4,752,740, granted June 21, 1988 to Steiminger. These systems did not however lend themselves to home use by a lay person.
With the increasing popular demand and need for pure water in the home, it was desired to provide a low cost and yet efficient device and method for obtaining purified water from impure water. There is now provided by the present invention a low cost device which is readily operated by a lay person and which provides purified water from tap water by a partial freezing method utilizing the home freezer.